It is known to use rigid polymers for house siding, shutters, roof vents, camper tops and the like. Typical polymers for these uses are rigid polyvinyl chloride (PVC), as described in U.S. Pat. No. 3,890,268, chlorinated polyvinyl chloride (CPVC), and acrylonitrilebutadiene-styrene (ABS) polymers. These materials have excellent original impact resistance. Unfortunately, outdoor exposure to sunlight and consequent environmental weathering of these rigid materials results in reduced impact strength. ABS materials are particularly vunerable to sunlight exposure and must be protected for extended outdoor applications. Exposure to weather also causes these rigid materials, especially colors other than white or pastel, to change in appearance which is aesthetically undesirable.